The moratorium would ban motorized mining on the full length of rivers and creeks that contain habitat for ocean-traveling salmon and bull trout. The moratorium is estimated to affect 84 percent of the state's waterways and would run until January 2018.

"It's important to protect our streams and rivers not only for the aquatic ecosystem, but also for the substantial recreational and fishing resources they provide, which contribute hundreds of millions of dollars to Oregon's economy annually," said Forrest English, director of Rogue Riverkeeper in Ashland. "Expecting the citizens of Oregon to subsidize recreational mining activity and shoulder the burden of their damages, I think, is unfair."

English plans to testify Monday in support of both bills. The Rogue River watershed is hit particularly hard by the impacts of suction dredging, he said.

Suction dredges work by sucking water, gravel and sand from a river bed through a nozzle that's powered by a pump. The material runs through a box and riffles that filter out the heavier gold and minerals. The remaining sediments and water are released through the back of the dredge.

Miners, such as Howard Conner of Salem, say taking sediment out of the river and redepositing it a short distance downriver causes no environmental harm. "You have introduced nothing new into the water," he said.

Conner, a program chairman of Willamette Valley Miners, enjoys suction dredging near Glendale about once a year. The money he and other mining tourists spend in town filling gas tanks and buying groceries helps sustain small, struggling towns who used to rely on logging, he said.

Conner blames environmentalists for attacking an activity he describes as "good, clean fun that the entire family can go down and participate in."

"They are attacking us front on to eliminate us from the forests and the streams, every place that they want to go and not be bothered by other Oregonians," Conner said. "It's really the height of extreme prejudice of one group of people against another."

Most recreational miners in Oregon must obtain a free permit from the Department of State Lands and a $25 permit from the Oregon Department of Environmental Quality.

State Lands last year issued 2,409 permits, and DEQ issued 1,941. Both agencies saw rising permit numbers in recent years. In 2009, State Lands issued 845 permits and DEQ issued 934 permits.

"When you get to the level (of mining) we're talking about here, it's just going to go up and you've got a problem," said Sen. Alan Bates, D-Medford, a leading supporter of both bills. "Everything we're getting keeps telling us this is not helping fish."

The proposed moratorium in Senate Bill 838 is intended to allow time for State Lands, DEQ, the governor's office, Native tribes and other groups to propose a revised regulatory framework on mining.

According to the bill, the new framework could include a consolidated, single permit; effective monitoring, compliance and enforcement mechanisms; adequate fee structures; or a flat-out prohibition on mining with motorized equipment in certain areas.

Mining permits currently restrict where, when and how mining can occur, but it's difficult for state agencies to monitor.

DEQ has one employee who goes out several weekends during the summer to see if miners are in compliance, said Bill Ryan, State Lands assistant director. Both DEQ and State Lands rely largely on partner agencies, such as the Oregon State Police, to enforce mining provisions.

"Essentially, we don't have people out in the fields that are monitoring where the mining activity is being done to determine whether or not it's in compliance," said Karen Tarnow, a senior policy analyst in DEQ's water quality division. "There's a lot of different ways they could be out of compliance."